An official guides the finishing horses away from the stricken The Cliffsofmoher after the running of the Melbourne Cup on Tuesday.
"Unfortunately, these things can happen to a horse galloping around the field at home", Irishman O'Brien said.
"Charlie was travelling head lad when I was with Godolphin in the United Kingdom and we used to head up to all the Northern tracks a lot of the time".
Melbourne Cup contender Cliffsofmoher has been euthanised on track after suffering a fractured shoulder.
"I was lucky enough to get a license five years ago and a few people asked me what two races I would like to win for Godolphin and thankfully I've just knocked the second one out in respect of the Derby and Melbourne Cup", Appleby said.
McEvoy's win on the 9-1 shot followed his Melbourne Cup triumphs on Almandin in 2016 and Brew in 2000. Race favourite Yucatan, also trained by O'Brien, came in a disappointing 11th.
Cross Counter is also a member of a family with which Sheikh Mohammed has been involved through four generations.
"Our thoughts are with animal lovers across the country who have been affected by this loss, and confronted by the very real risks posed by racing to the horses involved", Speechly added. "It's a dream. It has just been one of those fantastic years".
"I did promise (the kids) a swimming pool". He's the one who's encouraged us to take the chances in what we do internationally.
The idea that Sheikh Mohammed is heavily involved in the Dubai-based stable is nothing new - passionate about horses and the team, he is known as a hands-on leader of the "Boys in Blue".
UPDATES: THE horse that exited midway through the Melbourne Cup - the Aidan O'Brien-trained The Cliffsofmoher - has been euthanased.
The gelding could be back next year but is certain to carry a heavier weight if he runs after sneaking into this year's race with just 51 kilograms.
And there have also been the exploits of the world's top-rated horse, Winx, who smashed legendary sprinter Black Caviar's Australian win record in August and then late last month clinched a record fourth Cox Plate and 29th victory in a row.